The present invention is directed to wheels for supporting tracked-vehicles and, in particular, to the road wheels for tracked-vehicles that provide a rolling interface and support structure between the track and body of the vehicle.
Tracked-vehicles are a superior means of traversing varied off-road surfaces compared to vehicles equipped with conventional pneumatic tires. The tracks provide an increased driving surface and area of contact with the ground thereby enabling superior support of heavier vehicles on such varied terrain. In addition, tracks are more durable than conventional tires such that they are less susceptible to puncture by sharp or metallic objects.
Tracked-vehicles are utilized in military, forestry, and construction fields. Military vehicles employing track drive systems include, for example, the Advanced Amphibious Assault Vehicle (AAAV), the Bradley Fighting Vehicle, and Abrams tanks. Generally, the drive systems of such vehicles include a track, a drive sprocket, a track tensioner, and a series of road wheels that support the body of the vehicle and serve as a rolling guide interface to the track.
Existing road wheels for track drive systems on military vehicles are designed with a single-wall “dish” shape or an “I-beam” shape. Due to the weight of the tracked vehicles and the environments in which they are operated, these road wheels are subjected to high radial and lateral forces. When the vehicle is turning or traversing a slope at an angle, the lateral forces create particularly high stresses and strains on the road wheels. Significantly, as the wall thickness of an existing road wheel is reduced, the lateral strength decreases exponentially. Therefore, the high stresses and strains inflicted upon the road wheels dictate the use of a thicker wall and/or higher strength material for the existing single-wall shaped road wheels in order to prevent them from yielding and bending. This, in turn, results in road wheels of higher weight and/or cost.
The weight of a tracked-vehicle is always a concern, and particularly so for military vehicles, as weight affects power needs, fuel consumption, transportability, speed, and mobility of the vehicle. Further, present military combat situations involve fewer instances of heavy-duty tank conflicts. Therefore, there is an increasing need for more lightweight vehicles that are able to safely transport troops over a wide variety of urban, suburban, and rural terrains with a moderate level of armament and weaponry. It is essential that these tracked-vehicles, such as the AAAV and Bradley, be as light as possible in order to maximize performance and mobility.
Additionally, as financial resources are always limited regardless of the application in which the tracked-vehicle is operating, there is a strong motivation and emphasis to reduce costs without compromising the safety and ability of such vehicles. As such, road wheels of relatively high cost are not desired.
Therefore, a road wheel design is needed for track drive systems for vehicles that provides sufficient lateral and radial strength without necessitating heavier, thicker walls or costly higher strength materials.